1. Field of the Invention
The present invention relates to a data encryption method and apparatus thereof, and more particularly, to a data encryption method and apparatus thereof, which prevents a user from using received content data without authorization.
2. Description of the Related Technology
As the use of the Internet increases, the security of data communication on networks becomes more important. The Internet is advantageous since a user can easily obtain desired information. Yet, it is highly probable that data may be illegally circulated by an unauthorized distributor.
Hence, many efforts have been made in a data encryption method so as to enable only an authorized user to use content data. And, various kinds of encryption algorithm have been introduced.
Recently, services of providing moving picture data such as movies, animations, and the like via the Internet are increasing. And, such a content providing service is generally performed via a one-way transmission from a server to a local client.
Hence, the conventional content security is performed to mainly prevent a user from illegally accessing a server. However, as the content transmission technologies via the Internet become more diversified, content data, which has been downloaded from a server, may be stored in a client computer. In such a case, a user occasionally can use the stored data without such right. That is, even after an authorized period of time for rightful use expires, the user may access and use the stored data.
The moving picture data such as movie, animation, or the like has a large volume. Hence, if it generally takes a great deal of time to decrypt the encrypted data, practically it would be difficult to playback the data. Hence, an encryption method enabling to perform a quick decryption is needed to reduce the amount of time for playback of the data as well as to keep the reliance of the encryption.